From: Yury Norov <yury.norov@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Yury Norov <yury.norov@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: [PATCH 09/12] bitmap: optimize bitmap_remap() when 'new' is empty map
Date: Mon, 28 Aug 2023 11:43:49 -0700 [thread overview]
Message-ID: <20230828184353.5145-10-yury.norov@gmail.com> (raw)
In-Reply-To: <20230828184353.5145-1-yury.norov@gmail.com>
When 'new' map is empty, we can skip remapping entirely and replace it
with bitmap_copy().
Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
lib/bitmap.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 2e8deeb8bf99..50385d61e6ea 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -1003,6 +1003,11 @@ void __bitmap_remap(unsigned long *dst, const unsigned long *src,
bitmap_zero(dst, nbits);
w = bitmap_weight(new, nbits);
+ if (w == 0) {
+ bitmap_copy(dst, src, nbits);
+ return;
+ }
+
for_each_set_bit(oldbit, src, nbits) {
int n = bitmap_pos_to_ord(old, oldbit, nbits);
--
2.39.2
next prev parent reply other threads:[~2023-08-28 18:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-28 18:43 [PATCH 00/12] bitmap: rework bitmap_{bit,}remap() Yury Norov
2023-08-28 18:43 ` [PATCH 01/12] bitmap: add find_nth_bit_from() Yury Norov
2023-08-28 18:43 ` [PATCH 02/12] bitmap: add bitmap_weight_from() Yury Norov
2023-08-29 7:22 ` Rasmus Villemoes
2023-08-28 18:43 ` [PATCH 03/12] bitmap: add test for bitmap_remap() Yury Norov
2023-08-28 18:43 ` [PATCH 04/12] bitmap: add test for bitmap_bitremap() Yury Norov
2023-08-28 18:43 ` [PATCH 05/12] bitmap: update comment for bitmap_{bit,}remap() Yury Norov
2023-08-28 18:43 ` [PATCH 06/12] bitmap: add small_cont_nbits() optimization for bitmap_remap() Yury Norov
2023-08-28 18:43 ` [PATCH 07/12] bitmap: add small_const_nbits() optimization for bitmap_bitremap() Yury Norov
2023-08-28 18:43 ` [PATCH 08/12] bitmap: optiimze bitmap_bitremap() Yury Norov
2023-08-28 18:43 ` Yury Norov [this message]
2023-08-28 18:43 ` [PATCH 10/12] bitmap: separate handling of identity and remapping parts in bitmap_remap() Yury Norov
2023-08-28 18:43 ` [PATCH 11/12] bitmap: defer calculating weight of 'new' " Yury Norov
2023-08-28 18:43 ` [PATCH 12/12] bitmap: don't count bits from the beginning " Yury Norov
2023-08-29 7:33 ` [PATCH 00/12] bitmap: rework bitmap_{bit,}remap() Rasmus Villemoes
2023-08-29 13:38 ` Andy Shevchenko
2023-08-29 13:50 ` Yury Norov
2023-08-29 14:56 ` Andy Shevchenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230828184353.5145-10-yury.norov@gmail.com \
--to=yury.norov@gmail.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®